class Ball {
	public void throwball() { }
}
class SoccerBall extends Ball { 
    public void throwball() {
		System.out.println("Throwing soccerball"); 
    }
}
class TennisBall extends Ball { 
    public void throwball() {
		System.out.println("Throwing tennisball"); 
    }
}
public class TestBall {
    public static void main(String args[]) {
		Ball b1 = new Ball();
		SoccerBall b2 = new SoccerBall();
		Ball b3 = new SoccerBall();
                                b1.throwball();
                                b2.throwball();
                                b3.throwball();
                                b4.throwball();
    }
}
